The present invention relates generally to the field of ultrasonic transmission and in particular to a new and useful ultrasonic transducer arrangement for transmitting and receiving ultrasonic data and power to and from a barrier.
The concept of biasing an ultrasonic transducer surface against another surface for transmitting ultrasonic waves rather than fixing the surfaces together is known in the art. The prior art, however, does not teach or suggest evenly and symmetrically distributing the pressure between the surfaces for an unexpected advantage over the prior art that had previously applied the biasing pressure centrally, thereby possibly distorting the wafer or disc shaped ultrasonic transducer and degrading its performance.
U.S. Pat. No. 4,162,111 to Brown teaches a high temperature ultrasonic transducer in which a piezoelectric crystal is held in contact with an acoustical diaphragm by a spring which also electrically couples the back face of the crystal to an electrical signal source. An oil film between the diaphragm and crystal provides an acoustical coupling. Air is used to insulate the spring electrical connection from the wall of the transducer. The oil is said to be a high temperature diffusion pump oil like “Sanzovac 5” oil from Monsanto but this is a misspelling of SANTOVAC 5 which is a polyphenyl ether diffusion pump oil.
U.S. Pat. No. 3,745,829 to Franchi; U.S. Pat. No. 4,544,859 to Eoff; U.S. Pat. No. 4,649,754 to Zacharias; U.S. Pat. No. 4,746,831 to (chino; and U.S. Pat. No. 4,918,990 to Fowler et al., also all teach biasing an ultrasonic transducer against a surface rather than fixing it to the surface, using springs, clips or clamps. Although in U.S. Pat. No. 4,918,990 to Fowler et al. the transducer has a perimeter that is pressed by a spring, only one spring is used and the pressure may tend to cant the transducer rather than evenly press it against the inner surface of the electrode tip disclosed in this references.
A need therefore remains for an effective and efficient ultrasonic transducer arrangement, particularly for high temperature and high pressure environments.